feat: add fuzz_handle_client target

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lib/fuzz/fuzz_targets/fuzz_handle_client.rs

@@ -0,0 +1,43 @@
+#![no_main]
+
+use libfuzzer_sys::fuzz_target;
+use std::sync::Arc;
+use usbip_rs::mock::MockSocket;
+use usbip_rs::{
+    ClassCode, UsbDevice, UsbEndpoint, UsbInterfaceHandler, UsbIpServer,
+    hid::UsbHidKeyboardHandler,
+};
+
+fuzz_target!(|data: &[u8]| {
+    let rt = tokio::runtime::Builder::new_multi_thread()
+        .enable_all()
+        .build()
+        .unwrap();
+    rt.block_on(async {
+        let handler = Arc::new(UsbHidKeyboardHandler::new_keyboard());
+        let device = UsbDevice::new(0)
+            .unwrap()
+            .with_interface(
+                ClassCode::HID as u8,
+                0x00,
+                0x00,
+                Some("Fuzz HID Keyboard"),
+                vec![UsbEndpoint {
+                    address: 0x81,
+                    attributes: 0x03,
+                    max_packet_size: 0x08,
+                    interval: 10,
+                    ..Default::default()
+                }],
+                handler as Arc<dyn UsbInterfaceHandler>,
+            )
+            .unwrap();
+
+        let server = UsbIpServer::new_simulated(vec![device]);
+        let mock = MockSocket::new(data.to_vec());
+        let output = mock.output_handle();
+        let _ = usbip_rs::handler(mock, Arc::new(server)).await;
+        let output_bytes = output.lock().unwrap();
+        usbip_rs::fuzz_helpers::assert_usbip_responses_valid(&output_bytes);
+    });
+});